Android UI 由于 Robotium 无法找到 ImageButton 对象，测试有时会失败

Question

我正在尝试调试一个 Android UI 测试，该测试大约有 3% 的时间失败。

我们的测试 class 是这样开始的：

@RunWith(AndroidJUnit4.class)
public class ActionWidgetAdapterTest {

    private Solo solo;

    @Rule
    public ActivityTestRule<SampleContainer> mActivityRule = new ActivityTestRule<>(SampleContainer.class);

    // SampleContainer is used exclusively for the test case and extends AppCompatActivity

    @Before
    public void setUp() throws Exception {
        solo = new Solo(InstrumentationRegistry.getInstrumentation(), mActivityRule.getActivity());
    }

    @After
    public void tearDown() throws Exception {
        solo.finishOpenedActivities();
    }
    // rest of class
    // [...]
}

有问题的测试用例如下：

@Test
@LargeTest
@FlakyTest
public void testAddActions() throws Exception {

    final ArrayList<Action> actions = new ArrayList<>();

    // Action is our in-house version of the Action class from the Leanback library
    final Action a1 = new Action(0, "text1", R.drawable.action_button_focused);
    final Action a2 = new Action(1, "text2", R.drawable.action_button_focused);
    final Action a3 = new Action(0, "text3", R.drawable.action_button_focused);
    final Action a4 = new Action(1, "text4", R.drawable.action_button_focused);

    actions.add(a1);
    actions.add(a2);
    actions.add(a3);
    actions.add(a4);

    // handler for posting to the main thread
    Handler mainHandler = new Handler(mActivityRule.getActivity().getBaseContext()
                                                                 .getMainLooper());

    Runnable myRunnable = () -> {

        // add actions to adapter
        mActivityRule.getActivity().mActionWidgetAdapter.addActions(actions);
    };
    mainHandler.post(myRunnable);

    solo.sleep(1000); // pause to resolve any timing issues
    assertTrue(mActivityRule.getActivity().mActionWidgetAdapter.getItemCount() == 4);

    // test edge case - navigate all the way to the left
    solo.sendKey(Solo.LEFT);
    pressUpDownEnter();
    solo.sendKey(Solo.LEFT);
    pressUpDownEnter();
    solo.sendKey(Solo.LEFT);
    pressUpDownEnter();
    solo.sendKey(Solo.LEFT);
    pressUpDownEnter();
    solo.sendKey(Solo.LEFT);

    assertTrue(solo.getImageButton(0).isFocused());
    assertFalse(solo.getImageButton(2).isFocused());
}

测试用例在绝大多数情况下都通过了。但是执行assertTrue(solo.getImageButton(0).isFocused());时有小几率失败；发生这种情况时，Robotium 会抱怨“找不到 3 个 ImageButtons”。这似乎没有任何模式。我将Robotium框架升级到最新版本，但并没有解决问题。

有人知道我们做错了什么吗？

Answer 1

我相信我已经找到原因了。据我所知，问题是由于 tearDown() 中的竞争条件造成的。根据 Robotium 源代码，finishOpenedActivities() 通过发送三次后退按钮来工作。但是，这似乎是在单独的线程上完成的。因此，即使新的测试用例开始，命令也可能会继续发送，导致正在测试的应用程序从视图中消失，并导致 Robotium 无法读取 UI.

考虑到应用程序已经在每次测试结束时被杀死，finishOpenedActivities() 似乎有点多余。我把那行注释掉后就没有再出现这个问题

Android UI 由于 Robotium 无法找到 ImageButton 对象，测试有时会失败

Android UI tests occasionally fail due to Robotium being unable to find ImageButton objects

java

robotium

android-testing

leanback